With drivable bristled sections it is at times difficult to achieve a high bristle density on the bristle support, particularly when it is desired to secure the bristle tufts to the bristle support using a technique referred to as anchor tufting. In one example, drivable bristle supports of electric toothbrushes have a relatively small surface area for focusing the driving motion on the tooth surfaces—in particular when the drive performs an oscillatory rotational motion. In another example, special tuft configurations are desired on drivable bristled sections. For example, round bristle supports which are oscillated in a rotary motion are frequently fitted with power tips in the area of the toothbrush longitudinal axis, i.e., toothbrush tufts which are of a greater height and protrude beyond the other tufts so as to enable them to penetrate into interproximal spaces. Such bristle tufts on the outer circumference of the bristle support conveniently have an elongated contour with a narrow, longitudinally extended tuft cross-section, thereby enabling the interproximal cleansing effect to be improved in addition to enabling the dentifrice applied to the bristled section to be held better on the working surface.
Disclosed, for example, in EP 0835081 B1 are tufts which are arranged on the circumference of a circular, rotationally drivable bristled section in the region of the longitudinal axis and project beyond the tufts arranged further inside. While such extended tufts on the outer circumference of the bristled section indeed enable the cleansing effect on the interproximal spaces to be enhanced, the cleaning action on the tooth flank sections adjoining the interproximal spaces fails to be optimal as yet. On the other hand, such configurations of bristled sections cannot be moved really gently from one tooth to another, so that brushing motions of the brush head in the toothbrush longitudinal direction produce a prodding sensation.
Similarly constructed brush heads, which are rotationally drivable and include a central recess or depression in the working surface of the bristled section, are known from US-D 478,214, US-D 517,325 or US-D 455,556.
The provision of elongated bristle tufts on the outer circumference of the bristled section aggravates the aforementioned problem of being able to achieve a high bristle density on the bristle support when affixing the tufts by means of the anchor tufting technique, since such elongated bristle tufts have to be affixed with several anchor wires with corresponding space demands.
Proceeding from the foregoing, it is a desire to provide an improved electric toothbrush and an improved brush head therefore, which prevent the disadvantages of the prior art while developing the art further in advantageous manner. In particular, it is desirable to achieve a high bristle density on the bristle support without foregoing the possibility of securing the bristle tufts by the anchor tufting technique.